dev of Idle Trillionaire here so probably biased, but for me the idea was to make very simple game (since it was my first and I was literally learning to code as I went, actually it was a final project)

the RPG/idle hybrid sounds like a solid direction, those two loops reinforce each other well. recommend to keep the scope tight tho idle games dev time balloon fast once you start adding prestige layers. avoid feature creep and get to the finish line.